Skin slicing machine

ABSTRACT

A skin splitting machine having a band blade entrained over spaced pulleys. A pair of sharpening units are mounted one over and the other below a run of the blade. The sharpening units comprise a grinding disc having a frontal planar surface and are mounted so as to be vertically, horizontally and tiltably movable with respect to the edge of the blade.

United States Patent Repetto Nov. 20, 1973 [5 SKIN SLICING MACHINE860,530 7/1907 Cormany 83/174 3,395,595 8/1968 Braun et a1. 83/174 [75]Inventor: Sum Repem Mme, Italy 1,199,836 10/1916 Sweet 51 247 73Assigneez SJLA. Luigi Rizzi & C" Modena, 2,541,615 2/1951 Ruau 51/247Italy [22] Filed; Ann 12 71 :rimary EaigminlegTDonald R. Schran ttorneurt 6 man 21 Appl. No.: 133,032 y [30] Foreign Application Priority Data[57] ABSTRACT Apr. 14, 1970 Italy "23283 A/70 A Skin Splitting machinehaving a band blade em trained over spaced pulleys. A pair of sharpeningunits 83/l;t2,65i1/72;1t; are mounted one over and the other below a runof [58] Fie'ld ll 12 247 the blade. The sharpening units comprise agrinding disc having a frontal planar surface and are mounted 56]References Cited so as to be vertically, horizontally and tiltablymovable Orlow 83/174 with respect to the edge of the blade.

7 Claims, 8 Drawing Figures PAIENIEMnveo ms 3.772.951 sum 1 c; 5

INVENTOR SILV/O REPETTO "GENT PATENTEU NOV 2 0 I975 SHEET 2H 5 INVENTORW0 REPETTO BY 70M WW HGENT PMENTEUNHV 20 i975 Sill? 3i? 5 SKIN SLICINGMACHINE.

The present invention relates to a skin slicing or splitting machine,and in particular to apparatus for sharpening the blade thereof.

Conventional skin splitting machines for forming animal hides or thelike are provided with an endless belt type blade held taut between theends of a pair of spaced pulleys, at least one of which is driven tomove the blade longitudinally, thus permitting a new edge to bepresented to the skin at all times. The skin itself is conveyed betweena pair of rollers, one of which is also driven to move the skintransversely through the blade. Usually the upper conveyor roller isdriven and is provided with means for locating it at a predetermineddistance from the cutting edge of the blade to obtain the desiredthickness of the skin. The blade is furthermore provided with asharpened cutting edge inclined on both faces to form a cutting angle,the bisector of which is downwardly inclined to produce a thrust in theskin,

as it is being cut, toward the direction of the upper rol- I ler.

It is obvious that maintaining a sharp, exact and perfect cutting edgeis essential for accurate and efficient cutting of the skin,particularly when very thin slices are required. The slicing machine is,therefore, generally provided with means for continuously sharpening theblade, comprising a pair of rotating grinding discs aligned on eitherside or face of the blade. The discs are rotated about their centers andare displaceable relative to the edge of the blade to obtain tangentialpoints of contact of the proper and desired inclination to form thecutting edge.

In conventional devices, it is difficult and often impossible todetermine the exact position and location of the grinding discs andconsequently the accuracy of the cutting edge formed on the blade. Thisis particularly so since the position of the relative centers of the twodiscs is difficult to determine because of the constant variation andwear in the grinding discs themselves.

Another difficulty arises from the fact that conventional devices aremanually adjustable and hence depend solely upon the skill of theoperator. This presents a problem when it becomes necessary to changethe blade position in order to process different skins or to producedifferent thickness. In conventional'grinding discs the speed ofrotation must be varied as the result of their wear in order to maintaina constant peripheral speed with respect to the moving blade.

It is, therefore, an object of the present invention to provide a skinsplitting machine having a blade and sharpening arrangement overcomingand eliminating the drawbacks of the prior devices.

It is another object of this invention to provide a skin splittingmachine having a blade and sharpening arrangement which may beautomatically operated and which may be constantly varied to compensateautomatically for wear on the blade or on the sharpening disc.

It is a further object of the invention to provide a skin splittingdevice having a blade and sharpening arrangement in which a constantcutting angle is automatically maintained over long periods of use. Itis yet another object to provide a device of the type described which isof simpler construction and which is more economical to produce,maintain and operate.

According to the present invention, a skin splitting machine having anendless blade is provided with two sharpening units, one locatedaboveand the other located below the blade. Each-sharpening unit comprises acup-shaped grinding disc, the axial edge of which forms a planar frontalcutting surface. Each disc is mounted for rotation about its centralaxis and is provided with means for inclining or tilting the frontaledge relative to the surface of the cutting edge of the blade. Each discis also provided with means for vertical and horizontal displacement todefine 4 an accurate and exact tangential cutting angle with the edge ofthe blade, this means being provided with visible indicia indicating andclearly establishing the position of the disc relative to the blade.

Preferably, the apparatus is provided with means for automaticallyadjusting the vertical, horizontal and tilting positions of the discwith respect to the blade, with or without varying the cutting anglethus formed.

The device is also provided with means for advancing the blade relativeto the cutting disc to compensate for wear on the blade and formaintaining a constant uniform pressure on the blade itself.

Various other features and details are disclosed in the followingdescription and in the accompanying drawing wherein FIG. 1 is aschematic front elevational view of a skin splitting machine,

FIG. 2 shows a section of the sharpening device, taken on a horizontalplane along the line IIII of Flg.

FIG. 3 is a vertical section of the device, taken along the lineIII--III of FIG. 1,

FIG. 4 is a vertical section taken on line IV-IV of FIG. 1,

FIG. 5 is a longitudinal axial section of a grinding disc carrying unittaken on the vertical plane V-V of FIG.

FIG. 6 is a detail of one embodiment of the means controlling thevertical movement of the grinding disc, taken on the line for VI-VI ofFIG. 3,

FIG. 7 is a view similar to that of FIG. 6 and showing anotherembodiment of the control means, and

FIG. 8 is a schematic of the entire machine.

In the drawing, only as much of the machine as is required forunderstanding the present invention is shown. The skin conveyor rollersare schematically il lustrated, while the drive means, table means,removal or receiving means for the skin or carcass, and various otherdetails well known to those skilled in this art, are not shown.Reference, of course, can be made to the readily available technical andpatent literature for those details required.

The machine, generally depicted in the numeral 1, is provided with apair of pulleys 2 and 3 spaced laterally to either side of an openingwhich receives the skin or animal carcass. A continuous or endless bondor belt type blade 4 is held taut over the pulleys, and one of thepulleys is driven by a conventional drive means, such as an electricmotor directly connected to it by an intermediate gear arrangement. At asuitable point along the lower run of the blade 4, there is mounted ahousing 5 containing the sharpening mechanism and its adjustmentdevices. The sharpening'mechanism comprises two independent units 6 and7 the first of which is disposed above and the second of which isdisposed below the blade.

As seen in FIG. 2, the blade itself is held by a pair of carryingmembers 8 and 9 which are adapted to be advanced or retracted in thehorizontal plane so as to move the edge of the blade toward or away fromthe sharpening units. This arrangement provides for the compensation ofthe loss of material caused by wear of the blade itself during use andalso provides adjustment for the blade so that it may accommodatedifferent skins or be made to out different thicknesses. The car riermeans 8 and 9 are mounted by suitable mechanisms, such as that shownschematically in FIG. 2 and in more detail in FIG. 4, so as to move theblade horizontally. Each of the carriers 8 and 9 is mounted by anintermediate gear control means (seen in FIG. 4) to a shaft 10 connectedto a transmission gear box 11 controlled by means ofa drive chain 12.The chain 12 may be connected to a manual drive mechanism or may beautomatically operated by conventional control means or by the systemshown in H6. 6.

The sharpening units 6 and 7 are identical in construction and aremirror images of each other. Consequently, as shown in the drawing andas described herein, similar parts bear similar reference numerals and adescription of one of the units should suffice as a description of theother. As seen in FIGS. 2 through 5, each sharpening unit comprises afixed base bracket 13 secured to a frame or other supporting member ofthe machine. A vertically slidable member 14 is dovetailed with thebracket 13 so as to be slidable thereon. In turn, the vertical slide 14mounts a horizontal slide member 15 which is also dovetailed to it. Acylindrical slidable shaft 16 extends from the horizontal slide 15 andis rotatable about its central axis. This third slide or cylindricalshaft 16 supports a motor 17 and a grinding unit carried in a mandrelsleeve 18. The shaft of the motor 17 is provided with a pulley 19, whilewithin the sleeve 18 there is mounted a rotatable shaft 20 on suitableroller or ball bearings 18a. The lower end of the shaft 20 has a pulley21 while the upper end of the shaft secures a cupshaped grinding disc22. The pulleys l9 and 21 are interconnected by a drive belt 23. Themotor 17 is preferably an electric motor and is provided with the usualcontrol and operating means (not shown), whereby the belt 23 is causedto drive the grinding disc 22.

The fixed base 13 carries a control mechanism for moving the verticalslide 14, comprising a horizontal worm 24 having a hand wheel 25 at oneend and engaging at the other end with a worm wheel 26. The worm wheel26 is secured within a small body mounted above the bracket 13 and isfree to rotate but not to move axially. The worm wheel 26 is threadedabout an elongated screw 27 connected by a fixed extension 14a to theslide 14. Rotation of the hand wheel 25 will of course move the verticalslide 14 up and down with respect to the fixed bracket 13.

The horizontal slide 15 is displaced through a rotary shaft 28 to whicha hand wheel 29 is also secured. The shaft 28 is threaded and screwedthrough a correspondingly threaded bore in the slide 15 and is supportedon the fixed bracket 13 so that rotation of the wheel 29 will move theslide in a horizontal direction with respect to the fixed bracket 13.

The cylinder 16 is rotatably mounted on the slide 15 by means of anextension sleeve 16a which is dovetailed within the slide 15. Thecylinder 16 is held in position by a plurality of bolts 30, the heads ofwhich are movable in an annular groove 31. By loosening the nuts ofbolts 30, the cylinder may be rotated in its dovetailed mounting withrespect to cylinder 5 about the horizontal axis extending through thecenter of the cylinder. Both the slide 15 and the cylindrical sleeve 16aare provided with cooperating indicia 32 such as a vernier calibrationto make visual the relative rotation and position of the parts. Theslides 14 and 15 and the fixed bracket 13 may also have cooperatingindicia. However, the screws 24 and 28 are generally in themselvessufficient to define the extent of movement and relationship.

With the structure thus described, the grinding disc may be adjustedrelative to the vertical, horizontal and tangential angle of the bladeedge. Since the two sharpening units 6 and 7 are identical inconstruction, the cutting angle formed on the edge of the blade may bedefined by the individual tangential angles made by each cutting discwith the blade edge. These angles can be selectively varied to anydesired degree so that a desired and predetermined cutting angle canthus be fashioned. Preferably, the cutting angle is such that the thrustcreated by the blade in the skin turns the skin upwardly toward theupper roller of the skin conveyor.

Returning now to the supporting carrier for the blade 4, as describedpreviously in connection with FIG. 2, reference is made in greaterdetail to the mechanism seen in FIG. 4. The blade 4 is supported by aguide 33 which is provided with a forward slotted edge to receive it. Asuitable low friction blade holder 33a is provided about the rear edgeof the blade. A strip 34 of metal or other suitable material is locatedin the slot of the guide 33 and bears against the rear edge of theholder 33a. Abutting against the strip 34 is a block 35 which has athreaded bore into which a screw 36 is inserted. The screw 36 isprovided with a knob 37 at its outer end which has a worm exterior 37aengaging the shaft 10 described in connection with FlG.2. Thus, bymanually turning knob 37 or the shaft 10 or by automatically turning theshaft 10 through the transmission 11, the horizontal position of theblades may be adjusted relative to the grinding disc.

Manual operation of the slides 14 and 15 have been described. However,displacement may also be obtained automatically in the manner depictedby the ratchet and pawl system seen in FIG. 6 which, for example, isshown operating the vertical guide 14. This system comprises a ratchetwheel 25a which is connected to the hand wheel 25. An electromagnet 38having a displaceable core 39 carrying a hinged pawl 40 is provided. Thepawl 40 is urged by a spring 41 into engagement with the teeth of theratchet wheel 25a. A rear stop 42 limits the rear movement of the core39. By actuating the electromagnet 38, the core 39 is moved rearwardly,carrying the pawl 40 with it so as to rotate the ratchet 25a and hencecause rotationof the screw 24. A similar ratchet and pawl system may beapplied to control the shaft 10 or the shaft 28 if desired. The signalor pulse for operating the electromagnet 39 may be programed bycomputer; or it may be directly responsive to the rollers or other meanscontrolling movement of the hide or operation of the machine.

As seen more clearly in FIG. 5, the grinding disc comprises a cup-shapedmember having a cylindrical axial edge 22a provided with abrasivematerial which forms a planar frontal grinding surface. The cyupshapeddisc 22 is generally cylindrical in construction and fits over asupporting member 43 mounted over the shaft 20 of the mandrel unit.Suitable screw fasteners 44 and retainer means 45 are employed to securethe disc squarely on the supporting member 43. The provision of a planarfrontal surface along a relatively narrow edge provides an improvedgrinding surface for the blade even the blade and the grinding surfaceare both held in substantially shallow or sharp angular positions toeach other.

In FIG. 7, an hydraulic actuator 50 is shown as an alternate to theelectromagnetic actuator 38 shown in FIG. 6. The mechanical structure ofthe hydraulic actuator is basically the same as that seen in FIG. 6 andthe same reference numerals designate the same parts. The electromagnet,however, is replaced with piston and cylinder unit 51 and 52. The piston51 is fixed to the shaft 39 securing the pawl 40. The arrangement formsa double acting piston-cylinder and is provided with a pair ofinlet/outlet ports 53 and 54 which are connected to a source ofhydraulic fluid, a pump and similar conventional structure. Valvesinterposed in each of the lines 53 and 54 are responsive to a manual orautomatically applied signal, such as from a pulse generator or sourceof current. The valves in the latter case may be solenoid-operated.

FIG. 8 depicts schematically the arrangement of knife 4 in the machineas a whole. For proper splitting operation, the position of the knife isdetermined by the distance a between a plane passing vertically throughits cutting edge and the plane in which the axes of the top and bottomconveyor flywheel rollers T and S respectively lie. The configurationformed by the proper and predetermined distance a of the knife 4 fromthe wheels T and S tends to move the knife 4 horizontally away from therollers on pressure of the moving skin. The knife, however, is kept inits defined position by reaction of the pusher members 8 and 9 (FIG. 4).After some operation, the knife edge wears and the distance a becomesenlarged. The pusher 8 and 9 under operation of the lead screw and nutset 36 and 35 (FIG. 4) and by the worn gear l-37a permit repositioningof the knife edge at the predetermined optimum point.

Similarly, during operation the grinding wheels also wear and becomedisplaced. These may also be repositioned by adjustment of the screwmechanism 26-27 (FIG. which acts on spindle 20 and drive motor 17.

Thus, according to the present invention, apparatus is provided whichcan automatically compensate for knife wear by continuouslyrepositioning the knife and for grinding wheel wear by a similar action.

The operation of the device is as follows:

On beginning the cutting of a skin, the blade 4 is brought to the exactposition required for the desired thickness by the manual operation ofthe knobs 37 or by the operation of the shaft 10 so that the strips 34push the blade 4 into contact with the grinding surface. The grindingdiscs are inclined to a predetermined degree relative to the edge of theblade by rotation of the support 16. The predetermined angularrelationship can be set by conforming to the indicia or verniercalibration provided on the surface of the slide member and thecylindrical sleeve 16a. It will be apparent that, because of the readilyavailable and visible indicia, the exact angular relationship may bedetermined prior to setting of the device and even prior to contact withthe blade. Each grinding disc and motor unit is then horizontallydisplaced by operation of the motor slide 15 in the manner described. Itmay be simultaneously displaced vertically by operation of the slide 14until the exact position is reached for producing the desired cuttingedge on the blade 4. Because the cutting angles are parallel to theplanar frontal surfaces 22a of the discs 22, they are consequentlyrectilinear with the axis of the cylinder 16 and bear a direct angularrelationship to the angle indicated on the scale 32.

Operation of the splitting machine may then continue and the skinssuccessively split. During operation, wear on the discs 22 and on theblade 4 will both be observed and/or may be checked by the use ofsuitable automatic instruments. The wear on the disc 22 is compensatedby a gradual movement of the motor and disc unit in a verticaldirection. This gradual movement may be automatically obtained by meansof electrical pulses derived from a timing device and transmittedautomatically to the electromagnet 38, which consequently throughoperation of the core 39 and pawl 40 moves the wheel 24a and the screw24 to adjust the slide 14 with respect to the fixed bracket 13. Signalsmay also be obtained by using suitable counters, RAM devices, etc.

The advance of or repositioning of the knife and/or grinding wheels maybe controlled by a known magnetic detector which is located on themachine, so as traverse the knife edge. The magnetic detector controls aswitch provided with two positions, the first for operating the gradualmovement of the knife, the second to operate the gradual movement of thegrinding wheels position. Preferably, the two positions are takensequentially, that is the correction of the grinding wheels is only madeafter correction of the knife position. The second position of theswitch may be interlocked with a pair of timers by which the guidingwheel is repositioned according to a predetermined interval of operationof the actuator shown in FIGS. 6 and 7 (as for example 2 minutes). Thesecond timer may be used to provide the return pulse of short duration(e.g., 2 seconds). The degree of sharpening or action of the grindingwheels on the knife is a function of the time of interval between twosequential movements of the grinding wheels A greater degree ofsharpening can thus be obtained by shortening the interval of the firsttimer. A softer sharpening may be obtained by lengthening the intervalof the same timer.

The sequential movement of knife and grinding wheels is cyclicallyrepeated so that a constant adjustment and repositioning is made tomaintain the knife edge at the optimum distance a.

It will be obvious that the average wear on the grinding discs may bepredetermined. Suitable automatic devices may, therefore, be used toprovide the movement of the blade with a minimum of parts. It ispossible to obtain signals, indicia or other stimulae for moving thevertical, horizontal slides as well as the blade 4 by means of aphotoelectric cell or a magnetic detector or the like, each of whichwill produce a pulse or signal which may be used to control the rotationof the respective operating shafts. Preferably, the blade 4 is to bemaintained against the surface of the grinding disc with a uniformconstant pressure, thereby retaining true rectilinear relationshipbetween the blade and the grinding surface and a uniform cutting orgrinding action. During either manual or automatic adjustment, thetangential contacting points between the grinding disc and the blade 4remain constant and the cutting edge or cutting angle of the blade donot vary. As a result, horizontal, vertical and angular adjustments canbe made with the use of the simple mechanisms and structure describedherein as distinguished from the more complex and costly mechanismsknown in the prior art.

The mechanism for vertically and horizontally advancing the grindingdiscs and the mechanism for horizontally advancing the blade areinterconnected by suitable control means whereby the advance of one isstopped when the advance of the other takes place. Therefore,compensation for wear on either the blade or grinding discs may be madeindependently and without interference from the compensation made forthe other. In this manner, the blade may be kept in an exact positionand the advance of the grinding discs may be so regulated so that thesharpening pressure between the disc and the blade remains constant anduniform. Controls for advancing the grinding discs and advancing theblades are conventional in nature and may include a blade sensing deviceand control means for the slide operating shafts which are electricallyconnected in such a manner that, when the blade position sensing memberindicates that the blade is worn, it stops the advance of the grindingdiscs and begins an advance of the blade, returning it to the correctinitial position, and after which the device for advancing the grindingdiscs resumes its operation.

From the foregoing it will be obvious that there is provided a simpleand effective mechanism for effeciently controlling the sharpening ofendless blades in skin splitting machines. The device may be manuallyoperable or is readily operable by suitable electric, electronic, orother automatic mechanical means. The present invention overcomes thedrawbacks of the prior art by enabling the swift and efficientcompensation for wear on either the blade or grinding disc and formaintaining the blade and grinding disc in perfect condition at auniform and constant cutting angle so that uniform splitting of theskins is maintained throughout the operation of the machine.

Various modifications and changes may be made to the device asdescribed. The description is intended to be illustrative only of thepresent invention and is not intended to be limiting in any manner.

What is claimed:

1. Apparatus for sharpening the cutting blade in a skin strippingmachine, said cutting blade comprising an endless belt-type bladeentrained over a pair of spaced pulleys, said apparatus comprising apair of cupshaped grinding discs having a planar frontal surface, onedisposed on one side and the other one on the other side of one run ofsaid belt, means mounting each of said discs for rotation about thecentral axis thereof and for movably adjusting said discs vertically andhorizontally with respect to said blade, and for adjusting the angularposition of the planar frontal surface with respect to the edge of theblade, the mounting and adjusting means for each disc comprising abracket, a first slide mounted on said bracket for vertical movement, asecond slide mounted on said first slide for horizontal movement, and athird slide mounted on said second slide for rotation about its axis,said disc being rotatably journaled about a shaft mounted on said thirdslide, and means for independently moving each of said slides.

2. The apparatus according to cliam 1, including a motor mounted on saidthird slide and means connecting said motor and said disc whereby saidmotor operates said disc while simultaneously moving in a vertical,horizontal and rotary direction with it. 3. The apparatus according toclaim 1, including means for automatically moving selected ones of saidslides in response to a predetermined time interval.

4. The apparatus according to claim 1, including means for automaticallymoving selected ones of said slides in response to the relative wear ofsaid blade and said grinding discs.

5. The apparatus according to claim I, wherein said second and thirdslides are provided with cooperating indicia indicative of the relativedisplacement thereof and means for locking said slides in fixedpredetermined alignment.

6. The apparatus according to claim 1, including means for advancingsaid blade toward and away from said grinding discs.

7. The apparatus according to claim 6, including means interconnectingsaid blade advancing means and said means for independently moving eachof said slides whereby selective movement of said grinding discs andblade may be accomplished.

* i t I.

1. Apparatus for sharpening the cutting blade in a skin strippingmachine, said cutting blade comprising an endless belttype bladeentrained over a pair of spaced pulleys, said apparatus comprising apair of cup-shaped grinding discs having a planar frontal surface, onedisposed on one side and the other one on the other side of one run ofsaid belt, means mounting each of said discs for rotation about thecentral axis thereof and for movably adjusting said discs vertically andhorizontally with respect to said blade, and for adjusting the angularposition of the planar frontal surface with respect to the edge of theblade, the mounting and adjusting means for each disc comprising abracket, a first slide mounted on said bracket for vertical movement, asecond slide mounted on said first slide for horizontal movement, and athird slide mounted on said second slide for rotation about its axis,said disc being rotatably journaled about a shaft mounted on said thirdslide, and means for independently moving each of said slides.
 2. Theapparatus according to cliam 1, including a motor mounted on said thirdslide and means connecting said motor and said disc whereby said motoroperates said disc while simultaneously moving in a vertical, horizontaland rotary direction with it.
 3. The apparatus according to claim 1,including means for automatically moving selected ones of said slides inresponse to a predetermined time interval.
 4. The apparatus according toclaim 1, including means for automatically moving selected ones of saidslides in response to the relative wear of said blade and said grindingdiscs.
 5. The apparatus according to claim 1, wherein said second andthird slides are provided with cooperating indicia indicative of therelative displacement thereof and means for locking said slides in fixedpredetermined alignment.
 6. The apparatus according to claim 1,including means for advancing said blade toward and away from saidgrinding discs.
 7. The apparatus according to claim 6, including meansinterconnecting said blade advancing means and said means forindependently moving each of said slides whereby selective movement ofsaid grinding discs and blade may be accomplished.